Process of stabilizing phosphorus sulfide-oxygen containing organic compound reaction products against hydrogen sulfide evolution



United States Patent PROCESS OF STABILIZING PHOSPHORUS SUL- FlDE-OXYGEN CONTAINING ORGANIC COM- POUND REACTION PRODUCTS AGAINST HY- DROGEN SULFIDE EVOLUTION John M. Musselman, Brecksville, Ohio, assignor to The sabnglard Oil Company, Cleveland, Ohio, a corporation 0 o No Drawing. Application December 30, 1955, Serial No. 556,458

4 Claims. (Cl. 260-125) This invention relates to a process of reacting oxygencontaining organic compound-phosphorus sulfide reaction products with a sulfite to stabilize them against generation of hydrogen sulfide.

Phosphorus sulfide-organic reaction products are now well known lubricating oil additives. These compounds are reported in the literature to impart extreme pressure properties to lubricating oils and greases, and to increase their load carrying capacity and film strength. These additives are also claimed to check oxidation of the lubrieating base, and prevent sludge, carbonization and lacquer formation on cylinder and piston walls of internal combustion engines operating under high temperatures and pressures; they may also inhibit corrosion.

However, many additives which are reaction products of oxygen-containing organic compounds and phosphorus sulfide, although their engine use properties are usually excellent, have the disadvantage of generating suflicient amounts of hydrogen sulfide on storage or in use to be unpleasant. It has been demonstrated that this hydrogen :sulfide actually is not a by-product of the reaction in which the additive is prepared, but is formed by chemical reaction or decomposition involving the additive in some way, and that this generation is expedited by heat and 'in the presence of moisture. Hydrogen sulfide is generated :after all of the hydrogen sulfide remaining after preparaiion of the reaction product is removed or destroyed.

In order to satisfy industry requirements for stability against generation of hydrogen sulfide, phosphorus sulfide-organic additives should not liberate hydrogen :sulfide after storage or use for 72 hours at 150 F. The oxygen-containing organic compound-phosphorus sulfide additives presently available in commerce normally do not meet this requirement. An odor of hydrogen sulfide is ofiensive at concentrations above 3 p. p. m. A number of commercial lubricating oils taken at random containing a high concentration of an oxygen-containing organic compound-phosphorus sulfide additive have been found to exceed this.

- In accordance with the present invention, 'organic compound-phosphorus sulfide additives are stabilized :against generation of hydrogen sulfide by reaction with a :Slllfii, desirably in the presence of water, at a temperature .of at least 150 F. In this reaction hydrogen sulfide present in the additive is destroyed, and in addition the .additive is so changed chemically that hydrogen sulfide is no longer generated under the test conditions described hereinafter.

. In this reaction free hydrogen sulfide present in the oil and/or the additive is thought to be removed in accordance with the following chemical equation:

This is not the only reaction which takes place, since not onlyis free hydrogen sulfide removed, but also the additive is stabilized against further generation of hydrogen sulfide for periods up to 500 hours or more, as

' additive.

"ice

measured by the hydrogen sulfide stablity test. In this reaction, it is thought that the sulfur dioxide liberated by the sulfite reacts with mercaptan (SH) linkages in the phosphorus sulfide reaction product, converting adjacent pairs of SH linkages to disulfide (S-S) linkages. Disulfide linkages are not reactive with water, and therefore this conversion prevents formation of hydrogen sulfide in the presence of heat and/or moisture. Mercaptan linkages are well known to be unstable under such conditions and are lost with the production of hydrogen sulfide.

This theory is in accord with the available evidence. The reaction in accordance with the invention does not increase the sulfur content of the additive substantially. The sulfur content of the stabilized additive is not more than about 1.5% higher than that of the unstabilized In many cases, the sulfur content is actually reduced by the process. This shows that the process of the invention cannot be a sulfurization. Absence of a substantial change in sulfur content is understandable if sulfur dioxide only links SH linkages to form S$-- linkages, since this of course does not involve addition of sulfur to the molecule. 7

However, inasmuch as the structure of phosphorus sulfide-oxygen-containing organic compound reaction products has not been completely elucidated, this reaction is only a hypothesis. It has not yet been proved. A definite conclusion that can be made is that the sulfite reacts with latent hydrogen sulfide-producing components of the additive, and stabilizes them so that hydrogen sulfide is no longer generated within the requirements of the hydrogen sulfide stability test.

In the hydrogen sulfide stability test, the additives ability to generate hydrogen sulfide is determined as an 8% solution in an S. A. E. No. 20 lubricating oil by storing the solution in a closed container at F. until hydrogen sulfide is detected by moistened lead acetate paper held over the oil. This paper will turn gray or black if hydrogen sulfide is present in a concentration of about 1.0 p. p. In. over the oil. The time required before hydrogen sulfide is liberated is reckoned as hours to failure, and to pass the test the time must be at least 72 hours. The storage temperature of 150 F. is the maximum that would be encountered under most conditions of handling and distribution.

The 16-hour test is more severe than the hydrogen sulfide stability test. The treated additive is heated at 150 F. for 16 hours, and the H28 concentration in p. p. m. determined by removing the hydrogen sulfide from the oil with nitrogen and passing the resulting gas mixture through ammoniacal zinc sulfate solution. The precipitated zinc sulfide is determined iodometrically. A value of less than 0.1 p. p. m. in this test indicates that an 8% solution of the additive in a motor oil will operate at least 500 hours before failure under the conditions of the hydrogen sulfide stability test.

Oxygen-containing organic compound-phosphorus sulfide additives are well known to the art and per se form no part of the present invention, which relates only to the treatment thereof with a sulfite. However, the following brief description is given of these reaction products for the aid and convenience of those skilled in the art in understanding the additives to which the present invention is applicable.

Phosphorus sulfide-oxygen-containing organic compound additives may be made with direct admixture of the reactants or, if desired, in the presence of a diluent oil which may or may not subsequently be removed. In either case, the entire reaction mixture which is obtained is referred to herein as the additive. A lubricatingmil may be used as the diluent. The term diluent is used for convenience, but it is not intended to imply that'the diluent oil is'inert; it will 'lubricating oil.

the reaction product .inthe first instanceiszprepared in' take part in the reaction if it is reactive with the phosphorus sulfide under the reaction conditions.

The additives of .theipr'esent invention are primarily intended .fdruse by addition .to lubricating oils. Such 1o'ils after refinement, such. asby solvent extraction and solvent dewaxing, have mixed withthema small amount 7 --bf .the additive. It has. been foundin practice that the modified rosin, myristic acid, naphthalic acid, dichloropalmitic acid, naphthoic acid, benzoic acid, naphthenic acids, hydroxystearic acid, dihydroxybenzoic acids, hydroxynaphthenic acids, dihydroxystearic acid, chlorobenzoic acid, dichlorodihydroxystearic' acid, lactones, oxidized petroleum fatty acids or other oxygen-containing or acidic petroleum products, as oxidized wax, kerosene, gas oil 'or other oxidized petroleum oil.

additives can be made much more soluble in lubricating oilif they are prepared in .a lubricating oil. Many of the reaction products reacted with a 'sulfite inaccordance with the present invention, if .made without an'oil pres- A large variety of aliphatic amides are suitable. The

preferred amides are those which contain either an amido hydrogen (ahydro'gen directly connected to the nitrogen),

or an olefinic double bond, or both; Typical'amides'are en t, "can only ;be dissolved. with difficulty, if at all, in

Their. solubility is greatlyenhancedif the presenceof an oil. This procedure is preferred.

. The reaction'is usually complete in about 18 hours or less, generally ll-to 2 hours. The reaction time is a funct-io'n 10f. temperature, the amount of the sulfide that is to react, the degree of subdivision of the reactants, the efficiency of mixing, etc. V v

The oxygen-containing organic. compound or mixtures thereof may be reacted with the phosphoru'ssulfide or a mixture of phosphorus sulfides in ratios from 5 to about 60% byweight of the, phosphorus sulfide. Generally about to about 50% is the usual amount that will be used, depending upon the molecular weight of the oxy- -;gen-containing organic compound, and about 10 to 20% is especially desirable.

Phosphorus pentasulfide is preferred, although other phosphorus sulfides, such as phosphorus sesquisulfide {and phosphorusiftrisulfide, or mixtures thereof with phosphorus pentasulfide, may be employed. .Phosphorus V pentasulfide is least expensive and readily available, and

for this reason is used in the illustrative examples. I a The oxygen containing organic compound may contain ether group, or a mixture thereof. 7

I Alcohols, carbonyl compounds such as ketones, aldehydes, and amides, carboxyl compounds such as esters and acids, and ethers are typical classes of oxygen-con- ..taining organiccompounds. The compounds cancontain oxygen in the form of a hydroxyl, carbonyl, carboxyl, or

aplurality of functional oxygeugroups, i.'e., polyalcohqls polyacids, polyarnides, polyethers, ,polyketones, polyesters, and polyaldehydes. Many mixed classes also are available, such as hydroxy acids, esters, ethers,

amides, ketones, and aldehydes, Usually, from 1 to'3 like or unlike functional'oxygen groups are s'ufiicient although higher polyfunctional compounds 'could be utilized for special effects. Saturated and unsaturated aliphatic and cycloaiiphatic compounds, aromatic compounds, and mixed aliphatic-aromatic, aliphatic-cycloaliphatic and cycloaliphatic-aromatic compounds are ,Within the scope of the invention. Desirably, the compound has a;r atl 1 .=.r high molecular weight and a boiling .point above the reaction temperature, propertiesusu'ally found in compounds of at least eightcarbon atoms.

However, ifthe substance has a low boiling point, the reaction may be conducted under" pressure, if desired. Preferably compounds having twelve or more carbon atoms, and generally not over twenty carbon atoms, are

employed although compounds of up to 52 carbon atoms or more are suitable. Also, halogenated derivatives of any of these classes of compounds are suitable.

Illustrative ofsome conveniently applicable ester materials are: degras, lanolin, sperm oil, beeswax, ester Waxes, butyl stearate, ethyl lactate, methyl oleate, methyl palmitate, butyl ricinoleate, butyl phthalate, 7 methyl stearate, methyl dichlorostearate, methyl chloro-napht-henate, coconut oil, palm oil, babassu oil, hydrogenated linseed, coconut and other vegetable and fatty oils.

A few ethers 'are di .(dodecyl) ether, methyl stearyl ether, ethylene glycol monoethers and ethyleneglycol chlorohydrin.

Typical acids are palmitic acid, abietic stream,

7 those which correspond to a carboxylic acid obtainable RCON where "R is an aliphatic hydrocarbon radical and and X1 are hydrogen and/or a lower aliphatic substituent, such as methyl and ethyl up to amyl. The amide stock used maybe a mixture of amides of ditferent molecular weight or .difierent degrees of unsaturation. a It need not be pure and amounts of other amides may be present.

Typical alcohols whichmay be used include-lauryl alcohol, stearyl alcohol, alcohols derived from coconut.

oil; sperm oil, palm oil and cottonseed oil, degras, oleyl alcohol, and ootyl alcohol. a

Representative ketones are methyl dodecyl, xylyl heptadecyl, dioctadecyl, diheptadecyl, ethyl heptadecyLpropyl heptadecyl, and hydroxyphenyl heptadecyl 'ketones.

Palmitone (commercial dipalymityl 'ketone) is a readily availablehigher ketone. The'ketone stock'may beamixture of the ketones of difierent types or different molecular weights or both. I 7 The compound used in forming'the reaction product should be selected with reference to the use of thejfinal composition and properties desired in it, e. g., to give a reaction product having oil solubility or dispersibility.

. 'It will be understoodthat up to 90% of the oxygencontaining organic compound may be replaced in part by "a iion-oxygen containing organic compound reactive with phosphorus sulfide, such as saturated and unsaturated aliphatic amines, and aromatic and unsaturated aliphatic and'cycloaliphatic hydrocarbons. Large numbers of th'ese compounds have been used in the preparation of mixed phosphorus sulfide-organic reaction produetsyand are therefore well known to the art. 7 p

Amines of higher 'molecular'weight may housed, such as primary and secondary, saturated and unsaturated )tliphatic amines and unsaturated tertiary-aliphati'c 'amines,

such "as octadecyl 'arnin'e, dioctadecyl 1 amine, foctade'cynyl amine, 'hexa'decyl amine, octadecy-nyl 'dimethyl amine v and dodecyl amine.

in the case of a secondary or tertiary amine, having'fr'om one to five carbon atoms.

Other desirable "substitutes for a part of oxygencontaining organic compound are unsaturated hydro carbons having frome to' 2 '5 carbon atoms and one or more pairs of double or'ltriple bonded icarbonato'ms.

High molecular Weight olefin polymers 'having'h molecular weight above 150 up to about50,000 are very useful. One such olefin polymer is the so-called fmotor polymer 5? lm ce mor ;r vm ri wh afis: 1 9. 18 ais i mm Ca: and Crolefiiis bynonselectivejpolymeriz on with 'a phosphorus 'acid type'f'catalyst. Mot y r boils' in therngeirbiru to 500 F. with sen or por- These Preferably the 'ainine has an aliphatic radical of at least ten carbon atoms, theother substituent, v

hon-boiling inthe range from 120 to 400 F. g A polymer gasoline fraction maybe removed therefrom by fractional distillation to the 250 F. cut point, and. thisfraction is called reduced motor polymer. Its average molecular weight is about 145, and it preferably contains a major amount of branched chain olefins boiling below 600 F.

Another polyolefin which is especially useful is one which improves the viscosity indexof lubricating oil, which has a molecular weight of about 2,000 to 100,000 and which is substantially saturated. A commercially available material of this type is known as Paratone. This is -a polyisobutylene polymer having a molecular weight from 10,000 to 20,000, in solution in a lubricating oil in an amount to give a viscosity of about 3,000 SSU at 210 F.

Terpenes and turpentine are typical cycloaliphatic and mixed aliphatic-cycloaliphatic-aromatic hydrocarbons, of which p-cymene, camphorene, cyclene, bornylene, camphene, a-pinene, sylverstrene, dipentene and 1,8-terpin are examples.

The reaction of the individual reactants selected from the above classes may be carried out in the presence or absence of air or in an inert atmosphere such as nitrogen or hydrogen sulfide. It may also be carried out under pressure.

The reaction temperature varies with the organic compound and is readily ascertained. The optimum is in the range of 225 to 600 F., above thiophosphate formation, although a higher temperature which is below that at which the reaction product would be decomposed could be used. A temperature of at least 250 to 350 F. is preferred in many cases.

The final reaction mass is preferably centrifuged, filtered or settled and decanted in order to remove the by-product, sludge or other insoluble material. Any excess of a volatile constituent or diluent may be removed by distillation. If desired, the final product may be solvent-extracted with a suitable solvent, such as liquid propane, isopropyl alcohol, acetone or other solvent known in the art, or contacted with an absorbent, such as activated charcoal, silica gel, activated clay and the like.

Although the process of the invention does not involve a sulfuri zation, it is applicable to sulfurized additives. An element of the sulfur family can be incorporated into the additive by conventional sulfurization techniques. This sulfur can be incorporated by adding elemental sulfur or a compound which yields sulfur, such as by treating the reaction product therewith or treating a derivative of the reaction product therewith.

If additional reacted sulfur is to be present in the additive, about 0.01 to 2.0 and preferably 0.1 to-1.0 gram atomic Weights of sulfur per mole of the phosphorus sulfide is used. Additional reacted sulfur may be incorporated simultaneously with or after the formation and, cooling of the primary reaction product. If added afterwards, the mass is maintained at about 200 to 300 F for from a few minutes to several hours, and preferably about one hour. Selenium and tellurium function much in the same way as sulfur in this respect. Alternatively, the sulfur can be added to the metal, nitrogen base or ester derivative.

As is well known, phosphorus sulfide-organic compound reaction products may also be utilized in the form of their metal, nitrogen base or ester derivatives, or mixtures of these derivatives, with the original reaction product. These derivatives are formed from compounds capable of replacing an acid hydrogen atom in the phosphorus sulfide-organic reaction product, although the formation of the above derivatives may itself involve replacement of an acid hydrogen in the reaction product.

The metal derivatives may be formed from one or more metal compounds, such as their sulfides, oxides, hydroxides, carbides and cyanamides. The preferred metal are those of groups I, H and III of the periodic table,' s uch as potassium, sodium, calc'ium, magnesium,

2,2 13 IW i ie 7 beryllium, zinc, barium and aluminum. For some purposes, the heavier metals are especially useful, suchas chromium, cadmium, tin, lead, antimony, bismutlnarsenic and the like. j i

The metal derivatives may be formed by reacting the phosphorus sulfide-organic reaction product with the corresponding metal compound at temperatures in the range of about to about 350 F., a temperature in the range of about 180 to 250 F. being preferred; When a metal, nitrogen base or ester derivative contain ng subsequently added reacted sulfur is desired, there are two alternative ways of producing it: (1) the original or primary reaction product can be reacted with an ele ment of the sulfur family and this reaction product then converted into the metal derivative, or' (2) the primary reaction product can first be converted into the metal derivative and this derivative then reacted with an element of the sulfur family,

From about 0.2 to about 6.0 equivalents of a metal compound may be used per mole of the sulfide used in the sulfide-derived reaction product, preferably about 1.0 to about 3.0 equivalents. 4

The metal additive compounds, especially those fully saponified so as to have a high metal content, may be mixed with oils to form greases, with or without conventional soaps, and in such cases the metal additive compounds serve to thicken the oil as well as to stabilize it and impart'a detergent action.

The nitrogen base derivatives may be prepared by re: acting'the primary or sulfur-containing reaction product with one or more basic nitrogenous compounds, such as ammonia, organic amines or heterocyclic bases. Generally, ammonia and the gaseous or liquid organic amines are preferred, such as methyl amine, diethyl amine, butyl amine, trimethyl amine, ethyl propyl amine, and isopropyl amine. Polyamines may also be used. From about 0.25 to about 6.0 equivalents of the nitrogen base may be used per mole of the phosphorus sulfide in the primary reaction product, preferably about 1 to about 4 equivalents.

The ester derivatives may be prepared by reaction of the primary reaction product with one or more alcohols, or thioalcohols, i.- e., alkyl, aryl,'cycloalkyland heterocyclic compounds containing a hydroxyl or thiohydroxyl group. The term ester derivative is used herein in its generic sense to include esters of any of the above types of compounds. The ester derivatives may be formed by reacting the primary reaction product with the hydroxy or thiohydroxy compound at temperatures in about the range of 100 to 350 F., a temperature of 180 to 280 F. being preferred. From about 0.2 to about 6.0 equivalents of the esterifying agent may be used per mole of the phosphorus sulfide in the primary reaction product, preferably about 1.0 to about 4.0 equivalents.

It is. beneficial to have water present in the reaction mixture when forming the metal or nitrogen base derivative, and this may be introduced as water of crystallization or as a hydrate of the metal compound, or of the nitrogen base, or it may be introduced separately. '0

A plurality of metals or nitrogen bases or of esterifying agents or mixtures of any two or more thereof may be, used. If the amount of the metal nitrogen base or alcohol or combinations thereof is small, the final product may be a mixture of the initial reaction product and the metal nitrogen base or ester derivative.

Obviously the description herein of the preparation of phosphorus sulfide-oxygemcontaining organic compound reaction products cannot be exhaustive in view of space limitations. Further details of the preparation of these reaction products will be found in the following patents, which are well known to those skilled in the art:

2,142,998 Chittich 2,357,345 Musselmari 2,211,221 HHenderson 2,358,305 peek. I 1, 4 1Cojok weasel William 2,361,957

2,252,260 .,.-.Pr"1itt'on 2,362,624; Gaynor 2,257,750 Li -mm "'2',364, 283 H 7 2,257,751 Lincoln 7 j 2,364,284. Freiiler 2,261,047 Assert v 2,365,209 Muss'elman 2,308,427 Reehner 7 2,368,000 Cook 2,329,436 I Cook. j 1 ,3 ,0 Berger 2,337,868 Bil Well 2,375,060 Williams". 2,355,105 P ano's 2,375,061 Williams 7 2,356,074 V i 'l lie above as well as other patents will be found briefly discussed in the article fUse of phosphorus sulfide organic reaction products as lube, .oil, additives I by George. G. Pritzke'r .in National Petroleum 'News,

December 5, 1945 (vol. 37, No.49).

In accordance. with'the invention the phosphorus sulfide-oxygen-containing organic compound additive mixture is reacted with a sulfite under conditions such that" the sulfur content of the resulting additive is not I more than. about 1.5% higher thanthat of the starting additive. capable of liberating sulfur dioxide gas under the conditions of thereaction, not only of bisulfites and normal sulfites, MHSO3 and M803, but also of metabisulfites MSaOr, and hydrosulfites M8204. Exemplary of satisfactory sulfites are sodium sulfite, sodium bisulfite, sodium metabisulfite and sodium hydrosulfite, potassium sulfite potassium bisulfite, potassium metabisulfite and potassium hydrosulfitaba'rium sulfite, calcium bisulfite,

sulfite, and zinc hydrosulfite. 'In general, any inorganic sulfite can be used, of which the sulfites of metals of groups I, II and III of the periodic table are the most outstanding groups. 'Both anhydrous and hydrated salts.

can be used, and the higher the S02 content, the better.

7 Potassium metabisulfite is preferred.

The reaction proceeds at an elevated temperature, generally in excess of 150, F. and preferably in excess of 175 F. The upper limit is determined by, the sta-.

6 bility of the reaction product being treated andis not critical.

The reaction time is a function of the temperature,

sulfide (i. e., sulfur dioxide) concentration and pressure (because of the sulfur dioxide present), rate of mixing and like reaction conditions, and likewise cannot be definitely specified. At a reaction temperature of 175 to 200 -F., a reaction time of twohours or more is indicated-,while at more elevated temperaturesj, say 250 F., onehour is more than ample. In a commercial process, for maximum utiliiation of equipment, it wouldbe'pref- The term sulfite is inclusive of any sulfite p. p. m.) sulfur dioxide'by weight of the additive may besufficient to achieve good hydrogen sulfidewfstabil ity,

although the amount required depends on the additive. An amount of sulfite to furnish from 1 to 1.5 (10,000 to 15,000 p. p. m.) sulfur dioxidetby weight ofthe additive is usually preferred, Larger amounts maybe "d where desired, but obviously it is uneconomic to use more than the minimum required to achieve satisfactory stability. Experience has indicated that an amoiiht of sulfite to supply over sulfur dioxide will bewvast'efuL and amounts in excess of this are usually avoided.

These amounts are too'small to effect a sulfurization of the additive. Even an amount of sulfite to supply 10% sulfur dioxide will not under the reaction conditions increase the sulfur content of the additive to more than about 1.5 higher than that of the starting additive. The reaction may be carried out on an additive which 'is either in the impure state, as taken from the. reaction vessel in which it is prepared, or which has been subjected to conventional purification'steps, such as solvent extraction, filtration, or treatment with activated clay,

erable to e'iriploya reaction temperature which will permit a reaction time of one hour or less, i. e., a tempera- I tu're of 250 F. or over.

Becausefof the high reaction temperatures, gaseous sulfur di'tixide may be present in the reaction mixture. Therefore, the reaction is best conducted in pressure egui ment, at atmospheric or super-atmospheric pressures; The higher the pressure, up to a'limitin'g pressure, the.

less sulfite (i e., sulfur dioxide), is required; At a pres- -sure of five pounds per square inch above atmospheric, for example, one-seventh the amount of sulfite (i. e., sulfur dioxide) heeded. at atmospheric pressure is required. Also, better hyd'ro'gen sulfide stability is obtained at higher pressures. Pressures in the range from .5 to 30 pounds 1 square inch above, atmospheri'care ,convenient and practical, and give very satisfactory refsult's, and therefore are preferred. I

The'ieaction will proceedmore smoothly and the hydrogen sulfide stability of the fi'naladditive will be enhanced the reactionis started in the presence of a small amount of water, usually at least 0.25% water by weight of the reaction mixture, ormo're Large quantities are not eeessary s ce'w'ater is produeed as a byproduct of the "i'e'aetion, and actually for this reason it is net as set'forth above, The additive can contain free hydrogen sulfide since, as has been stated, the sulfite reacts with and eliminates free hydrogen sulfideias well as with the components present in the reaction product which gen'ei'w ate hydrogen sulfide upon storage.

The sulfite reaction can be carried out in the presence of a diluent. iff-the product is oil-soluble, the diluent can be a lubricating oil. If the additive has. been 'prepared without an oil (see column 2, starting at line 64) an oil preferably is added before the sulfite reaction. Th'e reaction mixture preferably should comprise 25 to by weight of a hydrocarbon oil of lubricating viscosity such as those available in commerce. 'Generally 'speaking, a greater proportion of 'suchjoils'in the reaction mixture 'vvill result in a less severe,.but more inefficient, reaction in accordance with the invention. Where the oil proportion is below 25%, low reaction temperatures Within the stated range may be desirable to avoid a loss in the potency of the treated additive or'reaction mixture.

In order to illustrate the invention, the following'spe 'cific examples are given. Obviously, a verylarge number of examples of application of the process of the invention "to the 'very'larg'e number of known phosphorus sulfide-oxygen-containing organic compounds could be given, in view of the very large number of such derivatives known to the art, but space requirements make it impossible to give more than one example "each for treatment of a few specific embodiments of representative phosphorus sulfide-oxyge'ri-containing organic com- 'pound reaction products.

Examples 1 t0 4 V I 9 tive). 67 parts of Red oil was then added and the mixture agitated for one hour at 300 F. It was then al- 10 s-ni b o k (SA Nc- 20.) wa ad T e re u in the following table are typical; 7 v p Vis. at Piston Bearing Example Sulflte Sludge, Acid 100 F Viscosity Skirt Ring Condition Demerit Corrosion, No. Percent Nos. (SSU) Increase No. Gms. Loss Used Oil 8. 4. 2 430 8. 0 Sludged 24. 2. 0 1. 2 1. 2 474 79 6.0 Free and Clean 9. 2 0.090 1. 3 l. 2 1 487 92 5. 5 dO 8. 9 0. 108 1. 0 1. 6 507 116 5. 0 do 8. 8 0. 143 1. 3 1. 2 480 87 6. 0 do 9. 4 0. 130 1. 5 l. 2 458 64 5. 5 d0 8.8 0.083

lowed to settle and decanted. The decanted-mixture was further mixed with 200 parts Red oil and the resulting reaction mixture contained 3.20% sulfur and 0.44% ash. It was then placed in a pressure vessel equipped with a paddle type stirrer and heated by an oil bath to prevent local overheating.

The solution was heated to 80 F., at which temperature 0.5% water by weight of the solution was added and a suflicient amount of the sulfite listed below added to liberate the equivalent of 1% S02 by weight. Thereafter the reaction mixture was heated to 250 F. at a rate of 57 F. per minute, and-heating continued at this temperaure for one hour. The pressure within the vessel ranged from to 50 pounds per square inch, depending upon the sulfite employed. At the end of this time the mixture was blown with air for 30 minutes at 250 F. and then filtered hot with the aid of 2% filter aid.

The treated additive was evaluated for hydrogen sulfide stability alone and in an 8% concentration in SAE No. lubricating oil, optical density, per cent ash and percent sulfur, with the following results:

The treatment markedly reduces the demerit rating and bearing corrosion, showing that the engine perform ance characteristics of the additive also are improved.

Example 5 23 parts of PzSs were mixed with 50 parts No. 225 Red oil to form a slurry, and the slurry added to 100 parts degras over. a V2 hour period at 275 to 280 F. Another 50 parts of Red oil were added and then the reaction mixture was agitated for one hour at 280 F.

The above reaction mixture was divided into two equal portions. One portion was mixed with 100 parts Red oil to form a reaction mixture containing 3.38% sulfur and 0.69% ash. This reaction mixture was then treated with potassium metabisulfite exactly as set forth in Examples 1 to 4. The treated reaction mixture is denoted Example 5 hereinafter.

Example 6 The second portion was reacted with barium hydroxide in order to form a barium derivative thereof as follows: 4% barium hydroxideand 1% calcium hydroxide were Sulfite Solubility, 16 Hour H2S Stability Test Example H2O, Wt. Color, Sulfur, Ash, 4% in 160 Test H23 Color, No. Percent O. D Wt. Wt. S. E. N. Evolution, 0. D.

Formula Wt. Per- Added Percent Percent Oil 1 p. p. m Hrs. to H s,

cent Used Failure p. p. m.

1;" 1 422 3. 20 0. 52 Cloudy" 478. 0 91. 8 16 51. 1 2; NBzS205- 1. 49 0. 50 364 3. l4 2- 18 Clear.. 44. 8 85. 5 280 2. 2 3 NazSzO; 1. 95 0. 50 822 3. 46 2. 29 d0 54. 6 80. 2 190 2. 2 KzSzO 1. 73 0. 50 336 2. 89 1. 89 37. l 81. 6 352 4. 4

160 SSU at 100 F.

Procedure II. yp engine Series 30 ethyl.

Engine speed 1200 R. P. M. Sump temperature. 300 F. Jacket temperature 212 F.

Air fuel ratio 15 to 1. Compression ratio 7 to 1. Catalyst; none.

For comparative purposes','the test values for piston skirt, acid number, naphtha insolubles, and,. i .the v s s y i ere se ar ad .XIhe e is n we is ts r dt de t s-) 1 1;: Q

A conventional acid-treated Mid-Continent lubricatadded'to the additive and the mixture heated for 4 hours at 180 F. and 1 hour at 250 F. The resulting product was mixed with parts Red oil to form a reaction mixture having a sulfur content of 3.25% and an ash weight of 3.04%. This product was then treated with potassium metabisulfite exactIy 'as in'Examples 1 to ..4, and the resulting composition. is denoted Example 6 hereinafter.

Example 7 A slurry was formed of 25 parts of Pass and 25 parts Spermafol (hydrogenated sperm oil having an iodine value of 6 to 7, a melting point of 50 to 52 C., a free fatty acid content, as oleic, of l to 2%, a saponification value of to 138, and about 36% of unsaponifiables) and this slurry was then added to 75 parts of Spermafol at 300 F. over hour. The mixture was then heated for one additional hour at the same temperature, mixed with 300 parts of Red oil, and then filtered after addition of 5% filter aid. The product analyzed, 3.51% sulfur and-0.36% ,ash., .12': .1

.This product was then treated with potassiummetai bisulfite exactly as set forth in Examples 1 to 4.

.t ions' thereof.

mess additives were then tested to; enlist eu'd' ayatogen sulfide stability as "reported below: I r

'Sulfite Solubility, 16 Hour H28 Stabil- H1O, Wt. Golor, Sulfur, Ash, 4%in 160 Test H28 ity Test Example Percent O.'D. Wt. Wt. S. N. Evolution, Hours To Formula Wt.'Per- Added Percent Percent 011 1 p. p. m. Failure cent Used 4 None None 980 3. 38 0. 69 126. 6 16 1. 73 0. '50 910 I 3. 56 l. 71 8. 1 500+ N one None 617 3.51 0. 36 358. 1 l6 1. 73 O. 50 630 3. 75 0. 96 Clear" 5. 6 256 None None 1, 080 3. 25 3. 04 .do 15. Q6 1. 73 0. 50 1,170 3. 71 3. 09 ado i- 4. 4 560+ I160 SSU at 100 F. e

improvement in hydrogen siilfide st'abilityis quite marked. The sulfur and ash weight are increased as well. i

Conventional SAE No. acid-treated Mid-Continent lubricating oils blended with 8% of these additives were then submitted to tests in accordance with the ethyl motor procedure set forth above in Examples 1 to 4. The results in the following table are typical:

efiect on asneonrerit. ,The potency of the product in engine performance is-affected only'slightly, if atall, and may even be improved. Consequently,'the products of the invention are of general utility as additives for oils or greases.

The amount of the final additive to be incorporated in an oil or grease depend upon the characteristics of the .oil or grease and the intended use. Some oils have more Vis. at 100 F. (SSU) Used Oil Viscosity Increase Acid No.

, Sludge, Example Sulfite Percent Ring Condition Demerit Free and 01mm.

' of a tendency 'to corrode metals or to form acids, sludges and lacquer depositsithanethe s, and such oils require larger quantities'of the addition agent. Also, oils that are intended for use at higher temperatures require larger .amounts of the additive.

taining organic compound additive is itself a lubricant, there is no upper limit. However, it may be uneconomical to include in the lubricant more of the additive than is H: S. EVO- lution, Before Treatment Additive of Example No.

Example Wt. me,

No. Percent Wt Sulfite Percent 16 Hrs. at 150 F. After Treatment i. I a

he'improvenient in hydrogen sulfide stability is quite striking. 7 V

'Aeoiii'paris'on of Examples" 1 to 10 shows that KzSz'Qaf and NazSzOs give the best all-around results," from the standpoint of color, hydrogen sulfide stability and engine performance. v t

The above workingexample's of specific embodiments are for illustrative purposes only and are not intended as limitations of. the invention. In view of'the foregoing disclosure, the. art will clearly understand the invention in its broadaspects, including variations and rnbdifiea- The process of the invention is capable of producing exceptionally odor-stable phosphorus suIfide-oxygen- ,70

. containing organic compounda'd'clitives. The treatment also may increase the sulfurcontent or these products, but if it cloes the sulfur content of-the final additive is not; more than about 1.5% higher than that of the startadditive. The treatment has, in general,}little era 7 5 V necessar to impart" "the desired ropel-ties.

er .0% wi be m s if desirefl,'the-additivfes of the inventio may be used together with other addniona' nts,fe. g., pour ointde pressa'nts' or fihn strength agent's. In some instances it i is desirable to include a lubricating oil containing'the additive as agentfor improving the clarity of the oil, e. g., lecithin, I'auryl' to the 'art, and i'n order to prevent foaming of-the oil it'is desirable-jib some cases to add small amounts of tetraamyl alcohol and the like, which are well known silicate, an alkyl carbonate or polyalkyl silicone.

All parts d percentages in the specification and claims;

are by weigh This application is 'a continuation-impart of applica- A process of sameness-same sulfide-oxygen;

containing organic compound 'adilifives against generatibn In generahfrom about 1 to about 10% of the additive is employed. Under some 7 circumstances, amounts as low as 0.01% show a significant irnprovement. .Since the phosphorus sulfide-oxygen-con-.

. Generally, not

of hydrogen sulfide which comprises treating the additive with a sulfite in an amount to supply at least about 0.5% up to about 5% sulfur dioxide at a temperature of at least about 150 F. but below a temperature at which the additive would be decomposed, and under conditions of pressure and time to efiect chemical reaction between the sulfite and hydrogen sulfide-producing components of the additive and produce an additive which has a sulfur content less than about 1.5% higher than that of the starting additive and which meets the requirements of the hydrogen sulfide stability test.

2. A process in accordance with claim 1 in which the reaction is carried out at a temperature of from about 175 to about 250 F.

3. A process in accordance with claim 1 which comprises etfecting the reaction with the sulfite in the presence of at least 0.25% water.

4. A process in accordance with claim 1 in which the 6 reaction is carried out under superatmospheric pressure.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PROCESS OF STABILIZING PHOSPHORUS SULFIDE-OXYGENCONTAINING ORGANIC COMPOUND ADDITIVES AGAINST GENERATION OF HYDROGEN SULFIDE WHICH COMPRISES TREATING THE ADDITIVE WITH A SULFITE IN AN AMOUNT TO SUPPLY AT LEAST ABOUT 0.5% UP TO ABOUT 5% SULFUR DIOXIDE AT A TEMPERATURE OF AT LEAST ABOUT 150* F. BUT BELOW A TEMPERATURE AT WHICH THE ADDITIVE WOULD BE DECOMPOSED, AND UNDER CONDITIONS OF PRESSURE AND TIME TO EFFECT CHEMICAL REACTION BETWEEN THE SULFITE AND HYDROGEN SULFIDE-PRODUCING COMPONENTS OF THE ADDITIVE AND PRODUCE AN ADDITIVE WHICH HAS A SULFUR CONTENT LESS THAN ABOUT 1.5% HIGHER THAN THAT OF THE STARTING ADDITIVE AND WHICH MEETS THE REQUIREMENTS OF THE HYDROGEN SULFIDE STABILITY TEST. 